Chemical-sensitization photoresist composition

ABSTRACT

Disclosed are novel high-sensitivity positive- and negative-working chemical-sensitization photoresist compositions capable of giving a highly heat-resistant patterned resist layer of high resolution having excellently orthogonal cross sectional profile without being influenced by standing waves. The composition contains, as an acid generating agent by irradiation with actinic rays, a specific cyano-substituted oximesulfonate compound such as α-(methylsulfonyloxyimino)-4-methoxybenzyl cyanide. The advantages obtained by the use of this specific acid-generating agent is remarkable when the film-forming resinous ingredient has such a molecular weight distribution that the ratio of the weight-average molecular weight to the number-average molecular weight does not exceed 3.5.

This is a divisional of Ser. No. 08/762,920, filed Dec. 10, 1996 nowU.S. Pat. No. 5,902,713.

BACKGROUND OF THE INVENTION

The present invention relates to a chemical-sensitization photoresistcomposition or, more particularly, to a photoresist composition, whichmay be of the positive-working type or negative-working type, containinga unique acid-generating agent capable of releasing an acid when exposedto actinic rays. The photoresist composition gives a patterned resistlayer having high heat resistance and high resolution with a highphotosensitivity of the photoresist composition without being affectedby the influences of standing waves so that the patterned resist layerhas an excellently orthogonal cross section.

It is a trend in recent years in the manufacturing technology of variouselectronic devices such as semiconductor devices involving the processof photolithographic patterning works that so-calledchemical-sensitization photoresist compositions are acquiring more andmore prevalence by replacing those of the traditional types by virtue ofthe high sensitivity and high resolving power as compared withconventional photoresist compositions. The chemical-sensitizationphotoresist composition mentioned above contains a radiation-sensitiveacid-generating agent which is a compound capable of releasing an acidwhen exposed to actinic rays so as to catalyze the solubilizing reactionand crosslinking reaction of the resinous ingredient in the positive-and negative-working photoresist compositions, respectively.

The chemical-sensitization photoresist compositions include two classesof positive-working and negative-working ones depending on the activityof the radiation-released acid either to increase or to decrease,respectively, the solubility of the film-forming resinous ingredient inthe composition in an aqueous alkaline solution as a developer. In otherwords, the chemical-sensitization photoresist composition ispositive-working when the film-forming resinous ingredient therein isimparted with an increase in the solubility in the alkaline developersolution and is negative-working when the film-forming resinousingredient therein is imparted with a decrease in the solubility in thealkaline developer solution.

Accordingly, a positive-working chemical-sensitization photoresistcomposition usually contains a polyhydroxystyrene and the like of whicha part of the hydroxy groups are substituted by solubility-suppressingacid-dissociable protective groups such as tert-butoxycarbonyl andtetrahydropyranyl groups while the film-forming resinous ingredient inthe negative-working chemical-sensitization photoresist composition isusually a combination of an acid-crosslinkable melamine resin, urearesin and the like with an alkali-soluble resin such as novolac resinsand polyhydroxystyrene resins optionally protected for a part of thehydroxy groups with the solubility-suppressing groups.

It is known that the resinous ingredient mentioned above in thephotoresist composition should have a narrow molecular weightdistribution expressed by the ratio of the weight-average molecularweight Mw to the number-average molecular weight Mn, i.e. Mw:Mn, inorder to ensure high resolution of patterning and high heat resistanceof the patterned resist layer.

The acid-generating agent heretofore proposed or currently used inchemical-sensitization photoresist compositions includes oximesulfonatecompounds as disclosed in Japanese Patent Kokai 1-124848, 2-154266,2-161444 and 6-67433, of which those oximesulfonate compounds having acyano group in the molecule are preferred as exemplified byα-(p-toluenesulfonyloxyimino)benzyl cyanide,α-(4-chlorobenzenesulfonyloxyimino)benzyl cyanide,α-(4-nitrobenzenesulfonyloxyimino)benzyl cyanide,α-(4-nitro-2-trifluoromethylbenzenesulfonyloxyimino)benzyl cyanide,α-(benzenesulfonyloxyimino)-4-chlorobenzyl cyanide,α-(benzenesulfonyloxyimino)-2,4-dichlorobenzyl cyanide,α-(benzenesulfonyloxyimino)-2,6-dichlorobenzyl cyanide,α-(benzenesulfonyloxyimino)-4-methoxybenzyl cyanide,α-(2-chlorobenzenesulfonyloxyimino)-4-methoxybenzyl cyanide,benzenesulfonyloxyimino-2-thienyl acetonitrile,α-(4-dodecylbenzenesulfonyloxyimino)benzyl cyanide,α-(p-toluenesulfonyloxyimino)-4-methoxybenzyl cyanide,α-(4-dodecylbenzenesulfonyloxyimino)-4-methoxybenzyl cyanide,p-toluenesulfonyloxyimino-3-thienyl acetonitrile and the like.

It is noted that each of the above named cyano group-containingoximesulfonate compounds has two aromatic groups in a molecule, one,substituting the α-carbon atom to which the cyano group --CN is bondedand, the other, forming the sulfonate ester. While the acid releasedfrom such a dually aromatic oximesulfonate compound by the irradiationwith actinic rays is therefore an aromatic sulfonic acid such asbenzenesulfonic acid and p-toluenesulfonic acid, achemical-sensitization photoresist composition formulated with such anoximesulfonate compound and a resinous ingredient having a narrowmolecular weight distribution mentioned above has a defect that thepatterning of the resist layer is susceptible to the influences ofstanding waves so that the cross sectional profile of the patternedresist layer is not exactly orthogonal but has wavy or undulated sidelines.

SUMMARY OF THE INVENTION

The present invention accordingly has an object to provide a novel andimproved chemical-sensitization photoresist composition, which may bepositive-working or negative-working, free from the above describedproblems and disadvantages in the prior art chemical-sensitizationphotoresist compositions by using, as the acid-generating agent, aunique cyano group-containing oximesulfonate compound, by virtue ofwhich the photoresist composition has a very high sensitivity to actinicrays and is capable of forming a patterned resist layer having anexcellently orthogonal cross sectional profile and high heat resistanceas well as high resolution of the pattern without being influenced bythe standing waves.

Thus, the present invention provides, as the first aspect of theinvention, a positive-working chemical-sensitization photoresistcomposition which comprises, in the form of a uniform solution in anorganic solvent:

(a1) 100 parts by weight of an alkali-soluble hydroxy group-containingresin such as a polyhydroxystyrene, of which at least a part of thehydroxy groups are substituted each by an acid-dissociable substituentgroup and the ratio of the weight-average molecular weight to thenumber-average molecular weight Mw:Mn does not exceed 3.5; and

(b) from 0.1 to 30 parts by weight of a cyano group-containingoximesulfonate compound, as an acid-generating agent, represented by thegeneral formula

    R.sup.1 --C(CN)═N--O--SO.sub.2 --R.sup.2,              (I)

in which R¹ is a monovalent aromatic group and R² is an alkyl grouphaving 1 to 4 carbon atoms and unsubstituted or substituted by halogenatoms.

The present invention further provides, as the second aspect of theinvention, a negative-working chemical-sensitization photoresistcomposition which comprises, in the form of a uniform solution in anorganic solvent:

(a2) 100 parts by weight of an alkali-soluble resin such as apolyhydroxystyrene, copolymer of hydroxystyrene and styrene and novolacresin, of which the ratio of the weight-average molecular weight to thenumber-average molecular weight Mw:Mn does not exceed 3.5;

(b) from 0.1 to 30 parts by weight of a cyano group-containingoximesulfonate compound, as an acid-generating agent, represented by thegeneral formula

    R.sup.1 --C(CN)═N--O--SO.sub.2 --R.sup.2,              (I)

in which R¹ is a monovalent aromatic group and R² is an alkyl grouphaving 1 to 4 carbon atoms and unsubstituted or substituted by halogenatoms; and

(c) from 3 to 70 parts by weight of an acid-crosslinkable resin such asmelamine resins, urea resins and guanamine resins.

Some of the cyano group-containing oximesulfonyl compounds representedby the general formula (I) are novel and not known in the prior art.Novel species of the cyano group-containing oximesulfonyl compounds canbe represented by the general formula ##STR1## in which R² has the samemeaning as defined above and each of R³, R⁴ and R⁵ is, independentlyfrom the others, an atom or group selected from the group consisting ofa hydrogen atom, alkyl groups having 1 to 4 carbon atoms, alkoxy grouphaving 1 to 4 carbon atoms and atoms of halogen, e.g., fluorine,chlorine and bromine, with the proviso that at least one of R³, R⁴ andR⁵ in a molecule is an alkyl group, alkoxy group or halogen atom.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As is described above, both of the positive-working and negative-workingphotoresist compositions provided by the present invention arecharacterized by the use of a specific cyano group-containingoximesulfonate compound of the general formula (I) which has, differentfrom conventional dually aromatic cyano group-containing oximesulfonatecompounds mentioned above, only one aromatic group bonded to the samecarbon atom as that to which the cyano group --CN is bonded. It is aquite unexpected discovery that replacement of the conventional duallyaromatic cyano group-containing oximesulfonate compound with the abovedefined specific oximesulfonate compound has an effect to overcome theproblems and disadvantages in the chemical-sensitization photoresistcompositions in the prior art. The improvement accomplished by thepresent invention is particularly remarkable when the film-formingresinous ingredient, i.e. component (a1) or (a2), has a narrow molecularweight distribution as defined by the ratio of the weight-averagemolecular weight Mw to the number-average molecular weight Mn notexceeding 3.5.

The film-forming resinous ingredient as the component (a1) in thepositive-working chemical-sensitization photoresist composition is analkali-soluble resin having hydroxy groups, a part of which aresubstituted each by an acid-dissociable substituent group. Thealkali-soluble resin suitable as the base material of the component (a1)includes homopolymers of hydroxystyrene, copolymers of hydroxystyreneand styrene or a styrene derivative, of which the molar fraction of thehydroxystyrene moiety is at least 70%, and copolymers of hydroxystyreneand (meth)acrylic acid or a derivative thereof as well as copolymers of(meth)acrylic acid and a derivative thereof, of which a part of thecarboxylic hydroxy groups are substituted by the acid-dissociablegroups. Among the above named hydroxy group-containing resins,homopolymers of hydroxystyrene and copolymers of styrene andhydroxystyrene are preferred.

The above mentioned styrene derivative to be copolymerized withhydroxystyrene includes α-methylstyrene, 4-methylstyrene,2-methylstyrene, 4-methoxystyrene, 4-chlorostyrene and the like. The(meth)acrylic acid derivative mentioned above includes esters such asmethyl (meth)acrylate, ethyl (meth)acrylate, 2-hydroxyethyl(meth)acrylate and 2-hydroxypropyl (meth)acrylate, (meth)acrylamide,(meth)acrylonitrile and the like.

The acid-dissociable group substituting a part of the hydroxy groups inthe above named hydroxy-containing resins to form the component (a1) inthe inventive positive-working photoresist composition is selected fromthe group consisting of tert-alkyloxycarbonyl groups such astert-butoxycarbonyl and tert-amyloxycarbonyl groups,tert-alkyloxycarbonylalkyl groups such as tert-butoxycarbonylmethylgroup, tert-alkyl groups such as tert-butyl group, alkoxyalkyl groupssuch as ethoxyethyl and methoxypropyl groups, cyclic acetal groups suchas tetrahydropyranyl and tetrahydrofuranyl groups, benzyl group andtrimethylsilyl group, though not particularly limitative thereto.

The degree of substitution by the above mentioned acid-dissociablegroups for the hydroxy groups in the hydroxy-containing alkali-solubleresin is preferably in the range from 1 to 60% by moles or, morepreferably, in the range from 10 to 50% by moles.

In the formulation of the positive-working chemical-sensitizationphotoresist composition of the present invention, the component (a1) ispreferably a polyhydroxystyrene resin of which a part of the hydroxygroups are protected by the substitution of tert-butoxycarbonyl groups,tetrahydropyranyl group, alkoxyalkyl groups, e.g., ethoxyethyl andmethoxypropyl groups, or a combination thereof.

The component (a2) in the negative-working chemical-sensitizationphotoresist composition of the invention is an alkali-soluble resinselected from the group consisting of novolac resins as a condensationproduct of a phenolic compound such as phenol, m- and p-cresols,xylenols, trimethyl phenols and the like and an aldehyde compound suchas formaldehyde and the like in the presence of an acidic catalyst,hydroxystyrene-based polymers such as homopolymers of hydroxystyrene,partially or completely hydrogenated polyhydroxystyrenes, copolymers ofhydroxystyrene with styrene or aiderivative thereof and copolymers ofhydroxystyrene and (meth)acrylic acid or a derivative thereof and(meth)acrylic resins such as copolymers of (meth)acrylic acid and aderivative thereof. The polyhydroxystyrene can optionally be substitutedby the above mentioned acid-dissociable substituents for a part of thehydroxy groups. The above mentioned styrene derivative and (meth)acrylicacid derivatives can be exemplified by the same monomeric compounds asgiven above for the component (a1).

Polyhydroxystyrene resins of a narrow molecular weight distributionhaving the value of Mw:Mn not exceeding 3.5 or, in particular, about 2.0are available on the market as a "monodisperse" resin and can be used assuch-as the base material of the component (a1) or as the component(a2). No commercial products are available, on the other hand, for thenovolac resin to be used as the component (a2) having the Mw:Mn value of3.5 or smaller so that a conventional novolac resin of broader molecularweight distribution is subjected to a treatment of fractionalprecipitation to selectively remove the low molecular-weight fractionsto such an extent that the fractionated polymer may have a Mw:Mn valuenot exceeding 3.5.

The alkali-soluble resin as the component (a2) is selected preferablyfrom the group consisting of cresol novolac resins, polyhydroxystyreneresins and copolymers of hydroxystyrene and styrene as well aspolyhydroxystyrene resins of which a part of the hydroxy groups aresubstituted by tert-butoxycarbonyl groups. These alkali-soluble resinscan be used either singly or as a combination of two kinds or moreaccording to need.

As is described before, the resin as the component (a1) or (a2) isrequired to have a narrow molecular weight distribution with a Mw:Mnvalue as small as possible or not exceeding 3.5 in order to ensure highheat resistance of the patterned resist layer and high patternresolution with the photoresist composition. The Mw:Mn value should bepreferably 2.5 or smaller or, more preferably, 1.5 or smaller for thepolyhydroxystyrene resins and should be preferably 3.0 or smaller forthe novolac resins in view of the difference in the molecular weightdistribution between different types of resins as a consequence of thequite different molecular structures. The weight-average andnumber-average molecular weights of the resins can be determined by thegel permeation chromatographic (GPC) method by making reference topolystyrene samples having known molecular weights.

The component (b) as an essential ingredient in both of thepositive-working and negative-working chemical-sensitization photoresistcompositions of the present invention is an acid generating agent whichis a specific cyano group-containing oximesulfonate compound representedby the above given general formula (I). In the formula, R¹ is amonovalent aromatic group such as phenyl, naphthyl, furyl and thienylgroups, optionally, substituted on the aromatic nucleus by one or moreof substituents such as halogen, e,g., chlorine, bromine and iodine,atoms, alkyl groups having 1 to 4 carbon atoms, alkoxy groups having 1to 4 carbon atoms and nitro groups. The group denoted by R² is a loweralkyl group having 1 to 4 carbon atoms, which can be a normal orbranched alkyl group, including methyl, ethyl, n-propyl, isopropyl,n-butyl, isobutyl, sec-butyl and tert-butyl groups as well as ahalogen-substituted lower alkyl group having 1 to 4 carbon atoms such aschloromethyl, trichloromethyl, trifluoromethyl and 2-bromopropyl groups.

While, as is mentioned before, the conventional dually aromatic cyanogroup-containing oximesulfonate compound releases an aromatic sulfonicacid by the irradiation with actinic rays, the acid released from theoximesulfonate compound of the general formula (I) by the irradiationwith actinic rays is a lower alkyl sulfonic acid or a halogenated loweralkyl sulfonic acid. It is the advantage of the present invention thatthe chemical-sensitization photoresist composition comprising this acidgenerating agent in combination with the component (a1) or with thecomponents (a2) and (c) is capable of giving a patterned resist layerhaving excellent heat resistance, pattern resolution and sensitivity toactinic rays with an excellently orthogonal cross sectional profile ofthe patterned resist layer.

Though not fully clear, the mechanism leading to the above mentionedunexpected improvement accomplished by the invention is presumably that,in contrast to the aromatic sultonic acid generated in a conventionalphotoresist composition, which is poorly susceptible to thermaldiffusion in the post-exposure baking treatment of the resist layerresulting in a wavy form of the cross sectional profile of the patternedresist layer due to the relatively large molecular dimension, inparticular, in the resinous layer consisting of a polymeric resin of anarrow molecular weight distribution, the (halogenated) lower alkylsulfonic acid having a smaller molecular dimension generated in theinventive photoresist composition is more diffusible in the resinouslayer in the course of the post-exposure baking treatment to accomplishan excellent cross sectional profile of the patterned resist layer.

Examples of the cyano group-containing oximesulfonate compound of thegeneral formula (I) include:

α-(methylsulfonyloxyimino)benzyl cyanide;

α-(methylsulfonyloxyimino)-4-methoxybenzyl cyanide;

α-(trifluoromethylsulfonyloxyimino)benzyl cyanide;

α-(trifluoromethylsulfonyloxyimino)-4-methoxybenzylc cyanide;

α-(ethylsulfonyloxyimino)-4-methoxybenzyl cyanide;

α-(propylsulfonyloxyimino)-4-methylbenzyl cyanide;

α-(isopropylsulfonyloxyimino)-4-methoxybenzyl cyanide;

α-(butylsulfonyloxyimino)-4-methoxybenzyl cyanide;

α-(methylsulfonyloxyimino)-4-bromobenzyl cyanide; and the like. Amongthe above named compounds, the first mentionedα-(methylsulfonyloxyimino)benzyl cyanide is a known compound disclosedin U.S. Pat. No. 4,451,286 but the other compounds are each a novelcompound not known in the prior art nor described in any literatures.

As to the synthetic method for the preparation of the cyanogroup-containing oximesulfonate compounds of the general formula (I), amethod similar to the method for the preparation of the dually aromaticcyano group-containing oximesulfonate compounds, as disclosed inJapanese Patent Kokai 1-124848, 2-154266 and 6-67433, is applicablehere, though not particularly limitative thereto. Namely, the compoundcan be obtained by the esterification reaction between an oximegroup-containing compound and sulfonic acid chloride in an organicsolvent such as tetrahydrofuran, N,N-dimethyl formamide, N,N-dimethylacetamide, N-methyl pyrrolidone and the like in the presence of a basiccatalyst or an acid acceptor such as pyridine, triethylamine and thelike. The oxime group-containing compound as one of the startingreactants in the above mentioned esterification reaction can be preparedby a known method described in The Systematic Identification of OrganicCompounds, page 181 (1980, John Wiley & Sons), Die MakromolekulareChemie, volume 108, page 170 (1967), Organic Syntheses, volume 59, page95 (1979) and elsewhere.

In the formulation of the inventive chemical-sensitization photoresistcomposition, the above named oximesulfonate compounds can be used eithersingly or as a combination of two kinds or more according to need.Although the preferable combination of two kinds or more of theoximesulfonate compounds depends on various factors such as thethickness of the resist layer, conditions of the post-exposure bakingtreatment, intervention of an anti-reflection coating layer between thesubstrate surface and the resist layer and so on, it is particularlypreferable in the negative-working chemical-sensitization photoresistcompositions of the invention, in particular, to use a combination ofα-(methylsulfonyloxyimino)benzyl cyanide andα-(methylsulfonyloxyimino)-4-methoxybenzyl cyanide in a weight ratio of1:2 to 2:1.

In the positive-working photoresist composition of the inventioncomprising the resinous ingredient as the component (a1) and theacid-generating agent as the component (b), an acid is generated fromthe component (b) in the areas of the photoresist layer irradiated withactinic rays so that the acid-dissociable substituent groups in thecomponent (a1) are dissociated to regenerate the hydroxy groups in theresin molecules resulting in an increase in the alkali-solubility of thecomponent (a1) in the development treatment to selectively remove theresist layer in the exposed areas giving a positively patterned resistlayer.

In the negative-working photoresist composition of the inventioncomprising the alkali-soluble resinous ingredient as the component (a2),the acid-generating agent as the component (b) and theacid-crosslinkable resinous ingredient as the component (c), an acid isalso generated from the component (b) in the areas of the photoresistlayer irradiated with actinic rays so that the acid-crosslinkableresinous ingredient serves for crosslinking of the component (a2) todecrease the alkali-solubility of the resist layer in the aqueousalkaline developer solution resulting in selective removal of the resistlayer in the unexposed areas to give a negatively patterned resistlayer.

The acid-crosslinkable resinous ingredient as the component (c), whichserves as a crosslinking agent for the component (a2), in thenegative-working photoresist composition of the invention, is notparticularly limitative and can be freely selected from those used inconventional negative-working chemical-sensitization photoresistcompositions. Examples of the acid-crosslinkable resinous material asthe component (c) include amino resins such as melamine resins, urearesins, guanamine resins, glycoluryl-formaldehyde resins,succinylamide-formaldehyde resins, ethyleneurea-formaldehyde resins andthe like having hydroxy or alkoxy groups. These resinous compounds canbe readily obtained by the reaction of melamine, urea, guanamine,glycoluryl, succinylamide or ethyleneurea with formaldehyde in boilingwater to effect methylolation or further by the alkoxylation reaction ofthe methylolated resin with a lower alcohol. Melamine resins and urearesins are preferred either alone or as a combination. Commercialproducts of such resins are available on the market including, forexample, those sold under the trade names of Nikalacs Mx-750 and Mw-30as examples of melamine resins and Mx-290 as an example of urea resins(each a product by Sanwa Chemical Co.). These resinous compounds as thecomponent (c) can be used either singly or as a combination of two kindsor more according to need.

Besides the above named resinous compounds preferred as the component(c), certain benzene compounds having alkoxy groups such as1,3,5-tris(methoxymethoxy) benzene, 1,2,4-tris(isopropoxymethoxy)benzene, 1,4-bis(sec-butokymethoxy) benzene and the like and certainphenolic compounds having alkoxy groups and hydroxy groups such as2,6-di(hydroxymethyl)-p-cresol, 2,6-di(hydroxymethyl)-p-tert-butylphenol and the like can be used as the component (c).

It is important that the above described essential ingredients, i.e.components (a1) and (b) or components (a2), (b) and (c), are containedin specified weight proportions in each of the inventivepositive-working and negative-working photoresist compositions. Namely,the amount of the component (b) is in the range from 0.1 to 30 parts byweight or, preferably, from 1 to 20 parts by weight per 100 parts byweight of the component (a1) or (a2), respectively, in respect ofobtaining good balance of the pattern-forming behavior, uniformity ofthe resist layer and developability. When the amount of the component(b) is too small relative to the component (a1) or (a2), no completepatterning of the resist layer can be accomplished with the compositionwhile, when the amount thereof is too large, a decrease is caused in theuniformity of the resist layer formed on the substrate surface alongwith a decrease in the developability of the resist layer not to give anexcellently patterned resist layer.

The amount of the component (c) compounded in the negative-workingphotoresist composition of the invention is in the range from 3 to 70parts by weight or, preferably, from 10 to 50 parts by weight per 100parts by weight of the component (a2) in respect of obtaining goodbalance in the properties of photosensitivity, uniformity of the resistlayer and developability. When the amount of the component (c) is toosmall relative to the component (a2), the photoresist composition cannotbe imparted with high photosensitivity to actinic rays while, when theamount thereof is too large, a decrease is caused in the uniformity ofthe resist layer formed on the substrate surface and in thedevelopability.

It is usual that the chemical-sensitization photoresist composition isused in the form of a uniform solution prepared by dissolving the abovedescribed essential ingredients and optional additives in an organicsolvent. Examples of suitable organic solvents include ketone compoundssuch as acetone, methyl ethyl ketone, cyclohexanone, methyl isoamylketone, 2-heptanone and the like, polyhydric alcohols and derivativesthereof such as ethyleneglycol, ethyleneglycol monoacetate,diethyleneglycol, diethyleneglycol monoacetate, propyleneglycol,propyleneglycol monoacetate, dipropyleneglycol and dipropyleneglycolmonoacetate as well as monomethyl, monoethyl, monopropyl, monobutyl andmonophenyl ethers of the above named glycols and glycol monoacetates andthe like, cyclic ether compounds such as dioxane and the like and estercompounds such as methyl lactate, ethyl lactate, methyl acetate, ethylacetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methylmethoxypropionate, ethyl ethoxypropionate and the like. These organicsolvents can be used either singly or as a mixture of two kinds or moreaccording to need.

It is of course optional that the photoresist composition of theinvention is admixed according to need with various kinds of optionaladditives having compatibility with the essential ingredients andconventionally used in photoresist compositions including, for example,auxiliary resins to improve the film properties of the resist layer,plasticizers, stabilizers, coloring agents, surface active agents and soon.

The photolithographic procedure the patterning of a resist layer on asubstrate surface using the inventive photoresist composition can beconventional as in the prior art. Namely, the surface of a substratesuch as a semiconductor silicon wafer is uniformly coated with thephotoresist composition in the form of a solution on a suitable coatingmachine such as spinners followed by drying of the coating layer to forma photoresist layer which is patternwise exposed through apattern-bearing photomask to actinic rays such as ultraviolet light,deep ultraviolet light, excimer laser beams and the like or irradiatedwith electron beams by patternwise scanning to form a latent image ofthe pattern. After a post-exposure baking treatment of the resist layer,the latent image is subjected to a development treatment by using anaqueous alkaline solution of, for example, tetramethylammonium hydroxidein a concentration of 1 to 10% by weight as a developer followed byrinse with water and drying to give a resist layer patterned with highfidelity to the photomask pattern.

In the following, the positive-working and negative-workingchemical-sensitization photoresist compositions of the invention aredescribed in more detail by way of examples as preceded by thedescription of Synthesis Examples for the preparation of severalcompounds used as the component (b) in the Examples. In the followingdescription, the term of "parts" always refers to "parts by weight".

SYNTHESIS EXAMPLE 1

α-(Methylsulfonyloxyimino)-4-methoxybenzyl cyanide was prepared in thefollowing manner. Thus, 51.0 g (0.29 mole) ofα-hydroxyimino-4-methoxybenzyl cyanide and a solution prepared bydissolving 44.0 g (0.43 mole) of triethylamine in 400 ml oftetrahydrofuran were introduced into a reaction vessel to form a uniformsolution which was chilled to and kept at -5° C. Into the solution inthe reaction vessel were added dropwise 36.5 g (0.32 mole) of mesylchloride over a period of 2 hours under agitation. The reaction mixturein the vessel was agitated at -5° C. for 3 hours and then at about 10°C. for additional 2 hours. The reaction mixture was freed fromtetrahydrofuran as the solvent by distillation under reduced pressure at30° C. to give 73.6 g of a solid residue as a crude product which waspurified by repeating recrystallization from acetonitrile to give 47.5 gof a white crystalline product having a melting point of 116° C., whichcould be identified to be the target compound from the results of theanalysis described below. The above mentioned yield of the productcorresponds to 64.9% of the theoretical value.

The infrared absorption spectrum of the above obtained product compoundhad peaks at wave numbers of 1187 cm⁻¹, 1265 cm⁻¹, 1378 cm⁻¹, 1606 cm⁻¹and 2238 cm⁻¹. The proton nuclear magnetic resonance (¹ H-NMR) spectrumof the compound in acetone-d₆ had peaks at δ=3.48 ppm, 3.93 ppm, 7.12ppm and 7.90 ppm. The ultraviolet absorption spectrum of the compound inpropyleneglycol monomethyl ether as the solvent had absorption bands atλ_(m) a x =233 nm and 324 nm with a molar absorption coefficient ofε=8100 and 13800, respectively.

SYNTHESIS EXAMPLE 2

α-(Ethylsulfonyloxyimino)-4-methoxybenzyl cyanide was prepared insubstantially the same manner as in Synthesis Example 1 described aboveexcepting replacement of 36.5 g (0.32 mole) of mesyl chloride with 40.1g (0.32 mole) of ethanesulfonyl chloride. The yield of the crude solidproduct was 75.0 g, from which 62.1 g of a white crystalline producthaving a melting point of 102° C. were obtained by repeatingrecrystallization from acetonitrile, which could be identified to be thetarget compound from the results of the analysis described below. Theabove mentioned yield of the product corresponds to 80.6% of thetheoretical value.

The infrared absorption spectrum of the above obtained product compoundhad peaks at wave numbers of 1178 cm⁻¹, 1267 cm⁻¹, 1375 cm⁻¹, 1606 cm⁻¹and 2238 cm⁻¹. The ¹ H-NMR spectrum of the compound in acetone-d₆ hadpeaks at δ=1.47 ppm, 3.68 ppm, 3.93 ppm, 7.12 ppm and 7.89 ppm. Theultraviolet absorption spectrum of the compound in propyleneglycolmonomethyl ether as the solvent had absorption bands at λ_(m) a x =233nm and 325 nm with a molar absorption coefficient of ε=7400 and 12500,respectively.

SYNTHESIS EXAMPLE 3

α-(n-Butylsulfonyloxyimino)-4-methoxybenzyl cyanide was prepared insubstantially the same manner as in Synthesis Example 1 described aboveexcepting replacement of 36.5 g (0.32 mole) of mesyl chloride with 50.0g (0.32 mole) of 1-butanesulfonyl chloride. The yield of the crude solidproduct was 90.0 g, from which 52.3 g of a white crystalline producthaving a melting point of 71° C. were obtained by repeatingrecrystallization from acetonitrile, which could be identified to be thetarget compound from the results of the analysis described below. Theabove mentioned yield of the product corresponds to 55.3% of thetheoretical value.

The infrared absorption spectrum of the above obtained product compoundhad peaks at wave numbers of 1186 cm⁻¹, 1268 cm⁻¹, 1369 cm⁻¹, 1606 cm⁻¹and 2238 cm⁻¹. The ¹ H-NMR spectrum of the compound in acetone-d₆ hadpeaks at ε=0.96 ppm, 1.52 ppm, 1.89 ppm, 3.65 ppm, 3.95 ppm, 7.14 ppmand 7.89 ppm. The ultraviolet absorption spectrum of the compound inpropyleneglycol monomethyl ether as the solvent had absorption bands atλ_(m) a x =233 nm and 325 nm with a molar absorption coefficient ofε=8000 and 13600, respectively.

SYNTHESIS EXAMPLE 4

α-(Isopropylsulfonyloxyimino)-4-methoxybenzyl cyanide was prepared insubstantially the same manner as in Synthesis Example 1 described aboveexcepting replacement of 36.5 g (0.32 mole) of mesyl chloride with 45.5g (0.32 mole) of 2-propanesulfonyl chloride. The yield of the crudesolid product was 88.0 g, from which 55.2 g of a white crystallineproduct having a melting point of 72° C. were obtained by repeatingrecrystallization from acetonitrile, which could be identified to be thetarget compound from the results of the analysis described below. Theabove mentioned yield of the product corresponds to 61.2% of thetheoretical value.

The infrared absorption spectrum of the above obtained product compoundhad peaks at wave numbers of 1186 cm⁻¹, 1267 cm⁻¹, 1368 cm⁻¹, 1606 cm⁻¹and 2238 cm⁻¹. The ¹ H-NMR spectrum of the compound in acetone-d₆ hadpeaks at δ=1.52 ppm, 3.93 ppm, 3.95 ppm, 7.13 ppm and 7.87 ppm. Theultraviolet absorption spectrum of the compound in propylenegllycolmonomethyl ether as thelsolvent had absorption bands at λ_(m) a x =233nm and 324 nm with a molar absorption coefficient of ε=6800 and 11000,respectively.

SYNTHESIS EXAMPLE 5

α-(Methylsulfonyloxyimino)benzyl cyanide was prepared in the followingmanner. Thus, 52.5 g (0.36 mole) of α-hydroxyiminobenzyl cyanide and asolution prepared by dissolving 44.0 g (0.43 mole) of triethylamine in400 ml of tetrahydrofuran were introduced into a reaction vessel to forma uniform solution which was chilled to and kept at -5° C. Into thesolution in the reaction vessel were added dropwise 49.0 g (0.43 mole)of mesyl chloride over a period of 2 hours under agitation. The reactionmixture in the vessel was agitated at -5° C. for 3 hours and then atabout 10° C. for additional 2 hours. The reaction mixture was freed fromtetrahydrofuran as the solvent by distillation under reduced pressure at30° C. to give 75.0 g of a solid residue which was purified by repeatingrecrystallization from acetonitrile to give 64.5 g of a whitecrystalline product having a melting point of 120° C., which could beidentified to be the target compound from the results of the analysisdescribed below and coincidence of the melting point with the knownvalue reported in literatures. The above mentioned yield of the productcorresponds to 80.0% of the theoretical value.

The infrared absorption spectrum of the above obtained product compoundhad peaks at wave numbers of 844 cm⁻¹, 902 cm⁻¹, 1191 cm⁻¹, 1386 cm⁻¹and 2240 cm⁻¹. The ¹ H-NMR spectrum of the compound in acetone-d₆ hadpeaks at δ=3.50 ppm, 7.62 ppm, 7.68 ppm and 7.97 ppm. The ultravioletabsorption spectrum of the compound in propyleneglycol monomethyl etheras the solvent had absorption bands at λ_(m) a x =222 nm and 281 nm witha molar absorption coefficient of ε=8780 and 10800, respectively.

SYNTHESIS EXAMPLE 6

α-(Methylsulfonyloxyimino)-4-bromobenzyl cyanide was prepared in thefollowing manner. Thus, 81.0 g (0.36 mole) ofα-hydroxyimino-4-bromobenzyl cyanide and a solution prepared bydissolving 44.0 g (0.43 mole) of triethylamine in 400 ml oftetrahydrofuran were introduced into a reaction vessel to form a uniformsolution which was chilled to and kept at -5° C. Into the solution inthe reaction vessel were added dropwise 49.0 g (0.43 mole) of mesylchloride over a period of 2 hours under agitation. The reaction mixturein the vessel was agitated at -5° C. for 3 hours and then at about 10°C. for additional 2 hours. The reaction mixture was freed fromtetrahydrofuran as the solvent by distillation under reduced pressure at30° C. to give 103.0 g of a solid residue which was purified byrepeating recrystallization from acetonitrile to give 81.8 g of a whitecrystalline product having a melting point of 128° C., which could beidentified to be the target compound from the results of the analysisdescribed below. The above mentioned yield of the product corresponds to75.0% of the theoretical value.

The infrared absorption spectrum of the above obtained product compoundhad peaks at wave numbers of 844 cm⁻¹, 902 cm⁻¹, 1191 cm⁻¹, 1380 cm⁻¹and 2238 cm⁻¹. The ¹ H-NMR spectrum of the compound in acetone-d6 hadpeaks at δ=3.50 ppm, 7.80 ppm and 7.88 ppm. The ultraviolet absorptionspectrum of the compound in propyleneglycol monomethyl ether as thesolvent had absorption bands at λ_(m) a x =226 nm and 292 nm with amolar absorption coefficient of ε=9270 and 13500, respectively.

EXAMPLE 1

A positive-working chemical-sensitization photoresist composition in theform of a uniform solution was prepared by dissolving, in 400 parts ofpropyleneglycol monomethyl ether acetate, 30 parts of a firstpolyhydroxystyrene having a weight-average molecular weight of 8000, ofwhich the Mw:Mn value representing the molecular weight distribution was1.5 and 39% of the hydroxy groups were substituted bytert-butyloxycarbonyloxy groups, 70 parts of a second polyhydroxystyrenehaving a weight-average molecular weight of 81000, of which the Mw:Mnvalue representing the molecular weight distribution was 1.5 and 39% ofthe hydroxy groups were substituted by ethoxyethoxy groups, 2 parts ofα-(methylsulfonyloxyimino)-4-methoxybenzyl cyanide, 0.3 part oftriethylamine, 0.2 part of salicylic acid and 5 parts of N,N-dimethylacetamide followed by filtration of the solution through a membranefilter of 0.2 μm pore diameter.

A silicon wafer was uniformly coated with the thus prepared photoresistsolution on a spinner followed by drying at 80° C. for 90 seconds togive a dried photoresist layer having a thickness of 0.7 μm. The resistlayer was exposed to KrF excimer laser beams on a minifying projectionexposure machine (Model NSR-2005EX8A, manufactured by Nikon Co.) invaried doses increased stepwise by an increment of 1 mJ/cm² followed bya post-exposure baking treatment at 110° C. for 90 seconds and thensubjected to a development treatment in a 2.38% by weight aqueoussolution of tetra- methylammonium hydroxide at 23° C. for 65 secondsfollowed by rinse for 30 seconds with water and drying. Thephotosensitivity of the composition represented by the minimum exposuredose, at which the resist layer on the exposed areas could be completelyremoved by the above described development treatment, was 5 mJ/cm².

Further, a resist layer patterned in a line-and-space pattern of 0.22 μmline width formed in the same manner as above was examined with ascanning electron microscope for the cross sectional profile of the linepattern to find that the cross section was excellently orthogonal andstarding upright on the substrate surface without waviness.

The heat resistance of the patterned resist layer was estimated byheating the line-patterned resist layer of 100 gm line width at variedtemperatures for 5 minutes followed by the microscopic examination todetect no collapsing or deformation along the shoulders of theline-patterned resist layer when the heating temperature was 120° C. orlower.

COMPARATIVE EXAMPLE 1

The formulation of the positive-working chemical-sensitizationphotoresist composition and the evaluation procedures of the same weresubstantially the same as in Example 1 excepting for the replacement ofthe first polyhydroxystyrene with the same amount of a thirdpolyhydroxystyrene having a weight-average molecular weight of 8000, ofwhich the Mw:Mn value representing the molecular weight distribution was4.5 and 39% of the hydroxy groups were substituted bytert-butyloxycarbonyloxy groups, replacement of the secondpolyhydroxystyrene with the same amount of a fourth polyhydroxystyrenehaving a weight-average molecular weight of 8000, of which the Mw:Mnvalue representing the molecular weight distribution was 4.5 and 39% ofthe hydroxy groups were substituted by ethoxyethoxy groups andreplacement of α-(methylsulfonyloxyimino)-4-methoxybenzyl cyanide withthe same amount of α-(p-toluenesulfonyloxyimino)-4-methoxybenzylcyanide.

The results of the evaluation tests were that the photosensitivity ofthe composition was 4 mJ/cm² and the heat resistance test of thepatterned resist layer indicated that collapsing along the shoulders ofthe line-patterned resist layer was found when the heating temperaturewas 120° C. while the cross sectional profile of the line-patternedresist layer of 0.23 μm line width examined with a scanning electronmicroscope was wavy indicating a strong influence of standing waves.

COMPARATIVE EXAMPLE 2

The formulation of the positive-working chemical-sensitizationphotoresist composition and the evaluation procedures of the same weresubstantially the same as in Example 1 excepting for the replacement ofα-(methylsulfonyloxyimino)-4-methoxybenzyl cyanide with the same amountof α-(p-toluenesulfonyloxyimino)-4-methoxybenzyl cyanide.

The results of the evaluation tests were that the photosensitivity ofthe composition was 5 mJ/cm² and the heat resistance test of thepatterned resist layer indicated that no collapsing along the shouldersof the line-patterned resist layer was found when the heatingtemperature was 120° C. or lower while the cross sectional profile ofthe line-patterned resist layer of 0.22 μm line width examined with ascanning electron microscope was wavy indicating a strong influence ofstanding waves.

COMPARATIVE EXAMPLE 3

The formulation of the positive-working chemical-sensitizationphotoresist composition and the evaluation procedures of the same weresubstantially the same as in Example 1 excepting for the replacement ofthe first polyhydroxystyrene with the same amount of the thirdpolyhydroxystyrene as used in Comparative Example 1 and replacement ofthe second polyhydroxystyrene with the same amount of the fourthpolyhydroxystyrene as used in Comparative Example 1.

The results of the evaluation tests were that the photosensitivity ofthe composition was 4 mJ/cm² and the heat resistance test of thepatterned resist layer indicated that collapsing along the shoulders ofthe line-patterned resist layer was found when the heating temperaturewas 120° C. while the cross sectional profile of the line-patternedresist layer of 0.23 μm line width examined with a scanning electronmicroscope was orthogonal and standing upright on the substrate surfacewithout waviness.

EXAMPLE 2

A negative-working chemical-sensitization photoresist composition in theform of a uniform solution was prepared by dissolving, in 560 parts ofpropyleneglycol monomethyl ether, 100 parts of a first copolymer of a85:15 by moles combination of hydroxystyrene and styrene having aweight-average molecular weight of 2500, of which the Mw:Mn valuerepresenting the molecular weight distribution was 1.5, 10 parts of aurea resin (Mx-290, supra), 1 part of a melamine resin (Mx-750, supra)and 3 parts of α-(methylsulfonyloxyimino)-4-methoxybenzyl cyanide.

A silicon wafer was uniformly coated with the thus prepared photoresistsolution on a spinner followed by drying at 100° C. for 90 seconds togive a dried photoresist layer having a thickness of 0.7 μm. The resistlayer was exposed patternwise to KrF excimer laser beams on theminifying projection exposure machine (Model NSR-2005EXBA, supra)followed by a post-exposure baking treatment at 130° C. for 90 secondsand then subjected to a development treatment in a 2.38% by weightaqueous solution of tetramethylammonium hydroxide at 23° C. for 65seconds followed by rinse for 30 seconds with water and drying.

The minimum exposure dose representing the photosensitivity of thecomposition for the incipient pattern formation was 8 mJ/cm². The crosssectional profile of the line-patterned resist layer having a line widthof 0.30 μm as examined on a scanning electron microscope was excellentlyorthogonal and standing upright on the substrate surface withoutwaviness.

COMPARATIVE EXAMPLE 4

The formulation of the negative-working chemical-sensitizationphotoresist composition and the evaluation procedures of the same weresubstantially the same as in Example 2 excepting for the replacement ofthe first copolymer of hydroxystyrene and styrene with the same amountof a second copolymer of hydroxystyrene and styrene in a molar ratio of85:15 having a weight-average molecular weight of 2500, of which theMw:Mn value representing the molecular weight distribution was 4.0 andreplacement of α-(methylsulfonyloxyimino)-4-methoxybenzyl cyanide withthe same amount of α-(p-toluenesulfonyloxyimino)-4-methoxybenzylcyanide.

The results of the evaluation tests were that the photosensitivity ofthe composition was 10 mJ/cm² and the cross sectional profile of theline-patterned resist layer of 0.35 μm line width examined with ascanning electron microscope was wavy indicating a strong influence ofstanding waves. Line-patterned resist layers having a line width of 0.30μm or smaller could not be formed on the substrate surface.

COMPARATIVE EXAMPLE 5

The formulation of the negative-working chemical-sensitizationphotoresist composition and the evaluation procedures of the same weresubstantially the same as in Example 2 excepting for the replacement ofα-(methylsulfonyloxyimino)-4-methoxybenzyl cyanide with the same amountof α-(p-toluenesulfonyloxyimino)-4-methoxybenzyl cyanide.

The results of the evaluation tests were that the photosensitivity ofthe composition was 12 mJ/cm² and the cross sectional profile of theline-patterned resist layer of 0.30 μm line width examined with ascanning electron microscope was wavy indicating a strong influence ofstanding waves.

COMPARATIVE EXAMPLE 6

The formulation of the negative-working chemical-sensitizationphotoresist composition and the evaluation procedures of the same weresubstantially the same as in Example 2 excepting for the replacement ofthe first copolymer of hydroxystyrene and styrene with the same amountof the second copolymer of hydroxystyrene and styrene as used inComparative Example 4.

The results of the evaluation tests were that the photosensitivity ofthe composition was 7 mJ/cm² and the cross sectional profile of theline-patterned resist layer of 0.35 μm line width examined with ascanning electron microscope was orthogonal and standing upright on thesubstrate surface without waviness. Line-patterned resist layers havinga line width of 0.30 μm or smaller could not be formed on the substratesurface.

EXAMPLE 3

A negative-working chemical-sensitization photoresist composition in theform of a uniform solution was prepared by dissolving, in 400 parts ofpropyleneglycol monomethyl ether, 100 parts of a first novolac resinprepared by the condensation reaction of a 6:4 by moles combination ofm- and p-cresols with formaldehyde having a weight-average molecularweight of 12000, of which the Mw:Mn value representing the molecularweight distribution was 3.5, 10 parts of the urea resin (Mx-290, supra),1 part of the melamine resin (Mx-750, supra) and 3 parts ofα-(methylsulfonyloxyimino)-4-methoxybenzyl cyanide.

A silicon wafer was uniformly coated with the thus prepared photoresistsolution on a spinner followed by drying at 90° C. for 90 seconds on ahot plate to give a dried photoresist layer having a thickness of 2.0μm. The resist layer was exposed patternwise to the i-line ultravioletlight of 365 nm wavelength on a minifying projection exposure machine(Model NSR-2005i10D, manufactured by Nikon Co.) followed by apost-exposure baking treatment at 100° C. for 90 seconds and thensubjected to a development treatment in a 2.38% by weight aqueoussolution of tetramethylammonium hydroxide at 23° C. for 65 secondsfollowed by rinse for 30 seconds with water and drying.

The results of the evaluation tests were that the photosensitivity ofthe composition for the incipient pattern formation was 25 mJ/cm² andthe cross sectional profile of the line-patterned resist layer of 2 μmline width examined with a scanning electron microscope was orthogonaland standing upright on the substrate surface without waviness.

COMPARATIVE EXAMPLE 7

The formulation of the negative-working chemical-sensitizationphotoresist composition and the evaluation procedures of the same weresubstantially the same as in Example 3 excepting for the replacement ofthe first novolac resin with the same amount of a second novolac resinprepared from the same m- and p-cresol mixture and having aweight-average molecular weight of 10000, of which the Mw:Mn valuerepresenting the molecular weight distribution was 5.6, and replacementof α-(methylsulfonyloxyimino)-4-methoxybenzyl cyanide with the sameamount of α-(p-toluene-sulfonyloxyimino)-4-methoxybenzyl cyanide.

The results of the evaluation tests were that the photosensitivity ofthe composition was 30 mJ/cm² and the cross sectional profile of theline-patterned resist layer of 2 μm line width examined with a scanningelectron microscope was wavy indicating a strong influence of standingwaves.

COMPARATIVE EXAMPLE 8

The formulation of the negative-working chemical-sensitizationphotoresist composition and the evaluation procedures of the same weresubstantially the same as in Example 3 excepting for the replacement ofα-(methylsulfonyloxyimino)-4-methoxybenzyl cyanide with the same amountof α-(p-toluenesulfonyloxyimino)-4-methoxybenzyl cyanide.

The results of the evaluation tests were that the photosensitivity ofthe composition was 25 mJ/cm² and the cross sectional profile of theline-patterned resist layer of 2 μm line width examined with a scanningelectron microscope was wavy indicating a strong influence of standingwaves.

COMPARATIVE EXAMPLE 9

The formulation of the negative-working chemical-sensitizationphotoresist composition and the evaluation procedures of the same weresubstantially the same as in Example 3 excepting for the replacement ofthe first novolac resin with the same amount of the second novolac resinas used in Comparative Example 7.

The results of the evaluation tests were that the photosensitivity ofthe composition was 30 mJ/cm² and the cross sectional profile of theline-patterned resist layer of 2 μm line width examined with a scanningelectron microscope was orthogonal and standing upright on the substratesurface without waviness.

EXAMPLE 4

A negative-working chemical-sensitization photoresist composition in theform of a uniform solution was prepared by dissolving, in 500 parts ofpropyleneglycol monomethyl ether acetate, 100 parts of the samecopolymer of hydroxystyrene and styrene as used in Example 2, 15 partsof a melamine resin (Mw-100LM, a product by Sanwa Chemical Co.), 3 partsof α-(methylsulfonyloxyimino)benzyl cyanide and 4 parts ofα-(methylsulfonyloxyimino)-4-methoxybenzyl cyanide.

A silicon wafer having an anti-reflection coating film was uniformlycoated with the thus prepared photoresist solution on a spinner followedby drying at 90° C. for 90 seconds on a hot plate to give a driedphotoresist layer having a thickness of 0.80 μm. The resist layer wasexposed patternwise to the i-line ultraviolet light of 365 nm wavelengthon the minifying projection exposure machine (Model NSR-2005i10D, supra)followed by a post-exposure baking treatment at 100° C. for 90 secondsand then subjected to a development treatment in a 2.38% by weightaqueous solution of tetramethylammonium hydroxide at 23° C. for 65seconds followed by rinse for 30 seconds with water and drying.

The results of the evaluation tests were that the photosensitivity ofthe composition for the incipient pattern formation was 30 mJ/cm² andthe cross sectional profile of the line-patterned resist layer of 0.30μm line width examined with a scanning electron microscope wasorthogonal and standing upright on the substrate surface withoutwaviness.

What is claimed is:
 1. A cyano group-containing oximesulfonate compoundrepresented by the general formula ##STR2## in which R² is an alkylgroup having 1 to 4 carbon atoms and unsubstituted or substituted byhalogen atoms and each of R³, R⁴ and R⁵ is, independently from theothers, an atom or group selected from the group consisting of ahydrogen atom, alkyl groups having 1 to 4 carbon atoms, alkoxy groupshaving 1 to 4 carbon atoms and atoms of halogen, with the proviso thatat least one of R³, R⁴ and R⁵ is an alkyl group, alkoxy group or halogenatom.
 2. The cyano group-containing oximesulfonate compound as claimedin claim 1 in which R² is a methyl group, R³ is a hydrogen atom, R⁴ is amethoxy group and R⁵ is a hydrogen atom.
 3. The cyano group-containingoximesulfonate compound as claimed in claim 1 in which R² is an ethylgroup, R³ is a hydrogen atom, R⁴ is a methoxy group and R⁵ is a hydrogenatom.
 4. The cyano group-containing oximesulfonate compound as claimedin claim 1 in which R² is a butyl group, R³ is a hydrogen atom, R⁴ is amethoxy group and R⁵ is a hydrogen atom.
 5. The cyano group-containingoximesulfonate compound as claimed in claim 1 in which R² is anisopropyl group, R³ is a hydrogen atom, R⁴ is a methoxy group and R⁵ isa hydrogen atom.
 6. The cyano group-containing oximesulfonate compoundas claimed in claim 1 in which R² is a methyl group, R³ is a hydrogenatom, R⁴ is a bromine atom and R⁵ is a hydrogen atom.